Answer:
angle plm+angle lpm+angle pml=180°[by angle sum property]
21°+angle lpm+38°=180°
59°+ lpm=180°
lpm=180°-59°
lpm=121°
lpm+npl=180°[by limear pair]
121°+npl=180°
npl=180°-121°
npl=59°
